WIP: Add menu to toggle devtools and refresh the app

This adds a "View" menu that has a "Reload" and a toggle devtools item. I've wanted this so much instead of commenting out a line in index.html to get access to the devtools. The menu is hidden from view until you press the Alt key.

I intend to hide this functionality behind some sort of developer flag on the command line. Not sure how to wire that up with my run script yet, though. Also, refresh is enabled from devtools, so I probably will remove it.

Are you :+1: for adding this kind of stuff to the app?

To finish it:

* [ ] Add keybindings for other platforms
* [ ] Hide behind some sort of `--dev` command line argument